Adjustable resistance elements



July 1, 1958 w. J. OESTREICHER ADJUSTABLE RESISTANCE ELEMENTS Filed July 12, 1954 1 IN VEN TOR. wARRa/ J. of: TRE/C HER .Bymm

ATTORNEY United States Patent ADJUSTABEE RESISTANCE ELEMENTS Warren J.-0estreicher, Flushing, N. Y., assignor to Ken- This invention relates to adjustable resistors and other adjustable circuit elements and more specifically to an adjustable resistor of the coated type.

One of the objects of the invention is an adjustable circuit element of simple and more or less standard construction which by the addition of a few screw machine or stamped parts can be made adjustable to a high degree of accuracy.

Another object of the invention is an adjustable resistor of substantially cylindrical shape and consisting of electrically conductive materials, the resistance of which is adjustable by a sliding contact controlled by a coaxial movement caused between a pair of terminal parts attached to the resistor.

A further object of the invention is a resistor of the usual type and of substantially cylindrical shape, provided at both ends with terminal members, one stationary and the other axially adjustable to permit accurate adjustment of resistance.

Still another object of the invention is a cylindrical resistance element of the usual type supported in an outer insulating sleeve having terminal devices at both ends thereof, one being fixed and the other being adjustable by a screw movement so as to permit axial movement of the resistance element within and with respect to the outer cylinder and the stationary terminal device attached thereto thereby to obtain variation of the resistance in a predetermined manner.

These and other objects of the invention will be more fully understood from the drawings annexed in which:

Figs. 1 and 2 in front and top elevations respectively show a resistor assembly embodying certain features of the invention.

Fig. 3 represents a cross section through Fig. 1 along line 1-1.

Fig. 4 represents a cross section through Fig. 2 along line 2-2 and on an enlarged scale.

Fig. 5 represents a partial cross section of another embodiment.

In Figs. 1 through 4, a resistor of the usual cylindrical type is shown to consist of carbon or any other resistive material determining the value of the resistance between predetermined limits. Cylinder 1 and coating 2 are closely but slidably surrounded by an outer cylinder made of plastic or any other insulating material as schematically indicated at 3.

Attached to or formed with one end of inner cylinder 1, there is a longitudinal screw member 4 in electrical contact with the body of cylinder 1 at one end thereof.

By turning or otherwise moving screw member 4 axially or radially or in both directions, one position of inner cylinder 1 can be adjusted with respect to outer cylinder 3 which is held in one hand of the operator while screw member 4 is held and rotated by the other hand of the operator or conversely.

Outer cylinder 3 is provided with two terminal devices 5, 6.

Terminal device 5 made for example of brass includes a 2,841,675 Patented July 1, 1958 See number of springy gripping prongs 7, S, 9 and 10 clamped over the outside of outer cylinder 3 and forming at its top a nut member 11 engaging the thread of screw member 4. Thus by holding outer cylinder 3 and terminal device 5 attached thereto in one hand,'the operator by turning screwmember 4 will move inner cylinder 1 in a. longitudinal or axial direction with respect to outer cylinder 3.

Supported on outer cylinder 3 close to the opposite end thereof there is the other terminal device 6 held by insulating ring 12 holding diametrically arranged thereon a pair of terminal contacts of angular shape 13, 14 attached to ring 12 by screws or eyelets 15, 16. Terminal contacts 13, 14 at one end 17, 18 permit attachment to the circuit and at the other end from curved sliders 19, 20 to engage the surface of inner cylinder 1 through openings 21, 22 provided in outer insulating cylinder 3.

Thus if under control of screw 4 inner cylinder 1 is moved in longitudinal or axial direction, contact is maintained at the other end of cylinder 3 through openings 21, 22 with the outer surface of inner cylinder 1 but at a distance varying and depending upon the longitudinal displacement of screw 4.

By increasing the length of outer cylinder 3 as shown in the modification of Fig. 5, a potentiometer type of adjustable resistor can be realized.

In this modification there is attached at the free end of outer cylinder 3 a third terminal device 23 which is substantially of the same type shown in Fig. 3 at 5 facing terminal device 5 and connected to resistor body 1 in exactly the same manner as terminal device 5 by means of a screw 24 adjustable in nut portion 25.

Thus movement of resistor cylinder 1 within outer cylinder 3 permits adjustable tapping of the total resistance derived from internal members 5 and 23.

The invention is not limited to the particular shape, form and arrangement of circuit elements and connections, and insulating and conducting elements, shown and described, but may be applied in any other form or manner whatsoever Without departing from the scope of this invention. It can particularly be applied with coated type resistors or any other coated type of circuit elements.

The invention can also be applied to other circuit elements or to the determination of other circuit values such as impedance, capacitance and reactance values, and generally to any other elements where a gradual adjustment of values is required and especially Where it is feasible to apply the value determining material in the form of an elongated body or in the form of a surface layer on such body by coating, printing or in any other way whatsoever, all this without departing from the scope of the invention.

I claim:

1. An adjustable circuit element comprising a first body determining the value of the circuit element, a second insulating body surrounding and slidably supporting said first body predeterminedly spaced therefrom, terminal means at one end of said first body in contact with one end of said first body and other terminal means including a coaxial ring on said second body spaced therefrom and from said first terminal means, at least one terminal strip extending longitudinally along said second body in the space between said ring and said second body, said terminal strip having one end projecting from said second body and another end in contact with a least one other portion of said first body being dependent upon the relative position of said first and second bodies, and an adjustable fastening member attached to said ring and holding said ring and said longitudinal terminal strip against said second body; said second body having at 3 least one opening permitting said terminal strip slidingly to engage said other portion of said surface layer.

2. Element according to claim 1, wherein said other terminal means include a pair of longitudinal terminal strips, and a pair of adjustable fastening means attached to said ring and holding said ring and said terminal strips against said first body and engaging said second body and engaging said first body at diametrical portions thereof and through, diametrical openings of said second body.

UNITED STATES PATENTS Wallace June 16, Wohl June 22, Rubinstein Oct. 31, Riley Aug. 24, Reid July 26,

FOREIGN PATENTS Great'Britain Jan. 28, 

